Method of process of treating fabric to render it impervious.



' paper being "UNITED STATES WALDO SPAULDING, OF EAST PEPPERELL,MASSACHUSETTS, ASSIGNOR TO VELLUMOID PAPER COMPANY, OF WORCESTER,

earner or tion,

MASSACHUSETTS,

A CORPORATION OF WEST VlRGlNlA.

METHOD 0R PROCESS OF TREATING FABRIC TO RENDER lT IMPERVlOUS.

are. 837,005.

Specification of Letters Patent.

Patented Nov. 27, 1906.

Application filed ay 5. 1905. Serial No. 259.033.

To all whom it ntwg concern:

A tank may be provided in which the Be it known that I, WALno SPAULDING,a casein olution can be kept heated to a concitizen of the United Statesof America, residing at East Pepperell, in the county of Middlesex andCommonwealth of Massachusetts, have invented a new and useful Method orProcess of Treatmg Fabric to Render impervious, of which the followingis a speci- 5 fication.

My invention relates to the method or process of rendering paper orother like material impervious; and the object of my invention is torender such fabric substantially impervious to water, grease, acids,See.

My invention consists in the method or process herein described.

In the treatment I employ as the agent in one of the steps a caseinemulsion, casein be ing, as is well known, the chief nitrogenousingredient of milk. This emulsion consists of about ten parts casein,eighty parts water, and 6.4 parts borax, by weight, and is prepared byfirst soaking casein in one-half the quantity of water for some twelvehours, more or less, then adding the balance of the water and heatingthe mass at a temperature of perhaps 100", stirring meanwhile until anemulsion of the proper constituency and homogeneousness is produced. TheboraX may be introduced at any convenient point during the preparationof the emulsion: Of course this formula may be varied somewhat in orderto meet different conditions.

The treatment may be applied while the mass of pulp is being formed intopaper, beginning the new treatment whenthe web of pulpy material leavesthe Fourdrinier wire or the cylinders, as the case may be, it then beingin a damp condition, but with the larger percentage of moisture removed,or such treatment may be applied to the finished paper. In any event,owever, the treatment of the paper from this point is the same whetherit be pulp in a web or the finished article. The treatment consistsfirst in saturating the paper with a solution of the casein emulsion,preferably while the latter is in a heated state, since a more rapidabsorption and more, complete permeation, impregnation, and deposit'ofthe casein Within the microscopic interstices throughout the body ofthe treated is thus brought about.

may be varied, depending,

stant temperature, the paper being through the tank and saturated duringits passage. Since it is more expedient, if for no other reason, to keethe paper being treated in constant motion and to handle it in acontinuous sheet or strip, I prefer generally to feed the untreatedpaper from a roll and to wind it onto a roll again after treatment. Asthe paper passes from the tank containing the casein solution thesurplus of the latter is removed from the surfaces of said paper bymechanical means, as pressrolls, rather than by simply allowing suchsurplus to pass off by gravity.

vAs before intimated, the casein emulsion is,

reduced with water for the purposes of the above step in the process,the amount of such reduction varying according to the weight and textureof the paper and the uses for which said paper is desired. It may,however, be stated that in a majority of cases a hot solution ofabeutonepart of the emulsion and about two parts of water, byweight,

gives the best results. After leaving the casein-bath and having thesurplus adhering to the surfaces removed the pa er is passed into orthrough a solution of ormaldehyde and water. The strength of thissolution as heretofore stated, upon the paper and uses for which t isdesigned. In the majority of cases, however, thirty-five-per-cent.solution, to five parts of water, by weight, gives the best results.This bath should be cold instead of hot in order properly to precipitatethe casein, though any particular degree of temperature is notessentially necessary. The effect of the formaldeyhde solution upon thecasein-emulsion-saturated paper is to precipitate the casein and renderit insoluble. As the paper comes from the formaldehyde-bath I preferthat the surplus adhering to the surfaces be removed by mechanical meansas before. The paper is then dried in any convenient manner. The dryingremoves all the'watery constituents and leaves the paper in condition toresist the absorption and passage of water, grease, 850., but not inproper condi tion for all commercial uses. To tem er and render thetreated paper soft and plia le and a solution of one part formaldehyde;

passed 4 adapted for most commercial uses, 1 subject and forcing suchmatter into all the microsco ic pores'or openings and into'the masses ofher, causing a'thorough commlnghng and incorporation with the fibers ofthe casein compound, and at the same time, as hereto fore indicated, achange (hydration) takes place, whereby the mass of fiber, fillingmatemg the rial, and formaldehyde becomes tempered and softened. Toheighten the tempering and softening effect, I may in some instancesintroduce glycerin into the tempering-bath, one twohundredths, involume, of glycerin giving the best results in most cases. 1

The aper is again dried, when it is in condition f r the market.

Should it be desired to remove all traces of acids and any disagreeableodor and taste that-may be present in the paper at'this time, it issimply necessary to ass it through a bath of water and a suitafilevolatile alkali. If the paper is to be subjected to the alkalibath, itislnot necessary to dry it between this bath and the tempering-bath.

By the term hydration as used herein I mean the subjection of the paper(after treatment with the casein solution and formaldehyde and drying)to moisture, whereby two actions, mechanical and chemical, appear totake place, the mechanical action being apparently thetemporaryabsorption of water analogous to the absorption of water by adry sponge and the chemical action beermanent union of water with thetreated f;

bric analogous to the union of water with tapioca, causing swelling, orlike the chemical combination of water with lime or cement.

By this-process a sheet or strip of pa er can be treated as rapidly asitis manu actured, as the time for exposure to the casein solution neednot be longer than the time required for it to become saturated, this ofcourse varying with different thicknesses and densities, and the lengthof time of exposure ma be fixed without checking the speed by maLng thetank of such length that the requisite time will elapse while the stripis passing through it and the guides so arranged as to maintain thestrip in position to be acted upon by such solution the requisite lengthof time. Only a few seconds exposure to the action of formaldehyde isrequired in. most instances;

What I claim as my invention,.and desire to secure by Letters Patent, is

1. The improvement'in the art of treating fabric to render thesameimpervious con- .sisting in first forming an emulsion of ten lpartscasein, eighty parts water and 6.4 parts orax by weight, saturating thefabric with said emulsion, then subjecting the fabric so saturated tothe action of formaldehyde,

then drying the fabric, same and then drying it. 2. The improvement inthe art of treating fabric torender the sameimpervious consisting informing a solution of casein, borax and water substantially in theproportions as hereinbeforedefined, then subjecting the fabric sosaturated before it is dried to-the-actioh then hydrating theof'formaldehyde, then drying the fabric, then hydrating the same andthen drying it.

-In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

' WALDO SPAULDING. Witnesses: I

GEORGE G. TARBELL, AROHIBALD G. Print.

